Check out Edith Fowke's various collections of folk songs. Admittedly, she concentrated on Canadian folk songs the most, but it's amazing how they spread. For example, one song you have on your list is "Red River Valley", which most people assume has to do with Texas or somewhere in the American west. It actually originated in Canada and dealt with the Red River Rebellion in what is now Manitoba. The story in the original words was of a volunteer soldier who came in to help put down the rebellion and who fell in love with an Indian maiden while there. The song was a lament from the maiden when she heard that her lover was going to be heading back east.